Specialized cutaneous Schwann cells initiate pain sensation

A newly discovered cell type for pain perception

Pain has been thought to be initiated by activation of free nerve endings without end organs in the skin. In contrast to this paradigm, Abdo et al. discovered a previously unknown meshlike organ covering the skin that senses dangerous environmental stimuli (see the Perspective by Doan and Monk). This organ is built from specialized glial cells located in the epidermal-dermal border and is sufficient and required for initiation of mechanical pain transduction.

An essential prerequisite for the survival of an organism is the ability to detect and respond to aversive stimuli. Current belief is that noxious stimuli directly activate nociceptive sensory nerve endings in the skin. We discovered a specialized cutaneous glial cell type with extensive processes forming a mesh-like network in the subepidermal border of the skin that conveys noxious thermal and mechanical sensitivity. We demonstrate a direct excitatory functional connection to sensory neurons and provide evidence of a previously unknown organ that has an essential physiological role in sensing noxious stimuli. Thus, these glial cells, which are intimately associated with unmyelinated nociceptive nerves, are inherently mechanosensitive and transmit nociceptive information to the nerve.